Transfer finger mechanism



' Feb. 4, 1969 I -J. c. MCMURRAY 3,425,073

. TRANSFER FINGER MECHANISM Filed June l.- 1966 INVENTOR John C. McMuwaq DQfo MA ATTORNEYS Sheet Filed June 1, 1966 INVENTOR John C. MCMQH (M DLfi fwQ WW ATTORNEYE United States Patent 3,425,073 TRANSFER FINGER MECHANISM John C. McMurray, Hamden, Conn., assignor to Textron, Inc., Providence, R.I., a corporation of Rhode Island Filed June 1, 1966, Ser. No. 554,543 US. Cl. -11 Int. Cl. B21k 1/44, ]/64, 27/02 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to metal working machine tools such as nut formers, headers and the like and more particularly to a transfer finger mechanism for such machine tools.

In the prior art machine tools of the type noted above, a metal workpiece is operated on at a number of stations to progressively work the workpiece. Such stations are provided with cooperating punches and dies and means are also provided for transferring the blank from one operation or station to the next. The means for transferring the blank is commonly referred to as a transfer mechanism, the fingers of which are arranged to receive and grip a blank ejected from a die by a knockout pin at one station and thereafter transfer the workpiece to the next station or die.

In the prior art machines, the fingers of the transfer mechanism position the workpiece so that it may be pushed out of the fingers and into the die by the punch. Thereafter, the transfer fingers are withdrawn so that the workpiece may be formed by the punch.

In certain situations, it is not always desirable that a punch be utilized to eject the workpiece from the transfer fingers. Additonally, the use of a punch to push the workpiece out of the fingers requires the accurately timed movement of the fingers and the punch with respect to each other, such that one does not interfere with the operation of the other. In other situations, it is not always feasible that the punch be utilized to position the workpiece within the die. For example, when a nose punch is used to form the head of a short shank workpiece, a nose punch cannot be conveniently employed to eject the workpiece from the fingers if the length of the workpiece is less than the width of the transfer finger mechanism.

Accordingly, to overcome such disadvantages, applicants invention incorporates as part of the transfer mechanism, ejecting means which when actuated as the transfer mechanism advances toward the die, forces the workpiece into the die. Thereafter, the transfer mechanism is withdrawn and the punch may advance upon the workpiece already held within the die. In this manner small shank workpieces may be placed in the die without the requirement of a pusher rod which must be accurately timed with respect to the movement of the transfer fingers.

It is therefore an object of this invention to provide a new and improved transfer mechanism for use in heading machines, nut formers and the like.

Another object of this invention is to provide a new andimproved transfer mechanism including means cooperating therewith for ejecting the workpiece into the die.

3,425,073 Patented Feb. 4, 1969 A further object of this invention is to provide a new and improved transfer mechanism including ejecting means which is actuated to eject a workpiece as the transfer mechanism advances with the workpiece toward the A still further object of this invention is to provide a new and improved transfer mechanism which inserts a blank into the die without the assistance of the punch.

Still other objects and advantages of the invention will in part be obvious and will in part appear from the specification.

The invention accordingly comprises the features of construction, combinations of elements and arrangement of parts which will be exemplified in the constructions hereinafter set forth and the scope of the invention will be indicated in the claims.

For a fuller understanding of the invention reference is had to the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a die block of a heading machine or the like, showing the transfer finger mechanism according to the invention applied thereto;

FIG. 2 is a top plan view of the transfer mechanism illustrated in FIG. 1;

FIG. 3 is an end view of the transfer mechanism with parts in section;

FIG. 4 is an enlarged front elevational view of the transfer finger mechanism according to the invention;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4 showing the ejecting means of the mechanism in the first position;

FIG. 6 is a view similar to FIG. 5, in which the ejecting means is shown in a second position;

FIG. 7 is an alternate embodiment of a transfer finger mechanism according to the invention; and

FIG. 8 is another alternate embodiment of a transfer finger mechanism according to the invention.

Only two dies or stations, A and B, are shown in the drawings, a pair of dies being provided with transfer fin gers. It will be appreciated, however, that several pairs of accompanying transfer mechanisms and associated dies may be used in practice. Only one transfer finger mechanism is shown for a clear understanding and concise description of the invention.

To illustrate the invention, FIG. 1 shows a portion of a frame 10 of a progressive header machine having a die bed 11 and a cut-off station 12. The cut-01f mechanism, which for-ms no part of this invention, delivers a workpiece to the die A, the workpiece being operated on in known manner by a punch cooperating with die A. The second operation is performed on the workpiece in die B. Operation of the punches associated with dies A and B occurs simultaneously. During this time period, the transfer finger mechanism generally shown at 13 is positioned as shown in FIG. 1.

FIGS. 1 and 4 best illustrate the cross-transfer motion or lateral motion parallel to the faces of the dies performed by the transfer fingers. As shown more clearly in FIG. 1, the transfer fingers 13 are biased to a gripping or clamping position in any suitable manner, one of which is shown, and are secured or carried by an oscillatorily mounted transfer arm 14. The fingers are shaped and spring-biased, such that they will automatically open upon engagement with a workpiece. The transfer arm and the transfer fingers, 14 and 13, respectively, preferably travel from the neutral posiiton shown toward die A to engage a workpiece held therein. Thereafter the transfer arm is moved outwardly from the face of the die A and oscillated in front of the die B. It is then advanced toward die B, such that the workpiece may be placed therein. Upon completion of this step, the arm 14 is moved laterally from the die B to its neutral position, as shown.

A carrier or transfer mechanism frame 16 is affixed to the base of the machine and supports a driving mechanism for oscillating the transfer arm 14. The driving mechanism comprises a cam 17 which may be adjustably secured on the side shaft of the machine in a known manner. A cam follower 18 at one end of a cam lever 19 is urged by a spring as shown, or other suitable means, against the cam 17. The lever 19 is pivotally oscillated about point 20 as is well known. A link 21 adjustably secured to the other end of lever 19 is pivotally secured in driving relationship to a geared rack 22. As indicated in the drawings, the link 21 is adjustable lengthwise. The rack 22 is therefore driven or reciprocated right or left, as shown in FIG. 1.

As best seen in FIG. 3, the rack 22 oscillatingly drives a pinion 23, a cam shaft 24 and an offset crank 25. A crank pin 26 is pivotally secured or journalled in the transfer arm 14 in any suitable manner. The pinion 23, shaft 24, crank 25 and pin 26 may be integral parts. As will be seen, the pin 26 is secured to the transfer arm 14 intermediate the end thereof. The other end of the transfer arm is slidably supported in a pivotal block 27. The block 27 is connected to or integral with a shaft 28 journalled in a bearing block 29. A push-pull screw 30 is provided to adjust the position of the block 29 and thus block 27, relative to the position of the pin 26 on the transfer arm 14. Adjustments of the block toward or away from the shaft 24 will vary the length of the are that the transfer arm travels between the dies. The length and/or pivot point of the transfer arm 14 is controlled by block 27 and the arm 14 is slidably held in the block by the pin 26. The other basic motion of the fingers 13, the motion normal to the faces of the die or in and out transfer, is best illustrated with reference to FIGS. 2 and 3, and will be described in connection therewith.

It will be further seen from FIG. 3, that the pinion 23 is laterally movable relative to the rack 22 within a suitable space provided in transfer frame 16 between the journal portions of the shaft 24, thus the shaft 24, crank offset 25 and pin 26 are free to move or reciprocate from right to left. The spool 32, integral with the free end of the crankshaft 24, is reciprocably driven by a lug 34 to impart such motion to crank 25 and therefore also reciprocate transfer arm 14 normal to the plane of the die face. It will be noted that the arrangement of the spool 32 and lug 34 allows crankshaft 24 to rotate while being oscillated. The guide block 27, associated shaft 28 and spool 31 are similarly reciprocated by means of a lug 33 while pivoting or oscillating in unison with the transfer arm 14.

The phantom lines in FIG. 2 indicate extreme reciprocal positions of arm 14 and fingers 13. The reciprocal movement of arm 14, block 27 and fingers 13 as a unit, normal to the faces of the dies A and B, is accomplished by the reciprocation of spools 31 and 32 operatively associated with opposed lugs 33 and 34 suitably connected to right angle lever 35. As illustrated in this figure, lever 35, also shown in part in FIGS. 1 and 3, is pivotally secured at 36 to the carrier frame 16. One arm of lever 35 carries lugs 33 and 34 and the other arm is secured to a link 37 at 41. The link 37 is similar to link 21 and is driven similarly by a second cam 38. The cams 38 and 17 are both adjustably afiixed to the side shaft of the machine. Intermediate cam 38 and link 37 is a cam roller 39 held against cam 38 and rotatably mounted on lever 40 which, in turn, is pivotally secured in a well-known manner to link 37 remote from the right angle lever 35.

The movement of the transfer arm 14, block 27 and fingers 13 may be adjusted by relative displacement of earns 17 and 38. In this manner, the transfer fingers can be oscillated between the dies as well as advanced toward or away from the dies as required to facilitate the transfer of the workpiece. It is to be understood thatthis is only one example of means for moving the transfer fingers between dies. It should be understood that equivalent or similar means could be used to facilitate the moving of the workpiece from one die and positioning it in another die.

Referring now to FIGS. 46, there is shown an alternate embodiment of the improved transfer mechanism according to the invention, having ejecting means supported therefrom. The ejecting means is shown at 50 and comprises a lever 51 pivotally supported from the transfer fingers 13 by a pin 52. The lever 51 is held by the transfer fingers 13 in a manner such that a portion 53 thereof may forcibly eject a workpiece held by the fingers. In order to actuate lever 51, there is provided a pin 59 slidably mounted in a bore formed in the die bed of the machine. In the transfer fingers 13 there is provided an opening 60 to permit the pin 59 to pass therethrough and engage lever 51. The pin 59 may be moved by means (not shown) to rotate lever 51 or, in the alternative, stop means (not shown) may be employed to hold the pin 59 in place. In either case, as the transfer fingers advance on die B, the lever 51 may be pivoted to eject the workpiece.

In FIG. 6 there is shown the position of the lever 51 when the workpiece 55 has been pushed substantially into the die B.

FIG. 7 shows the preferred embodiment of the invention. In place of a pin 59 held in the die bed 11, a pin having a flange portion 66 is supported in a slot 67 having a flange 68 formed therein. As the transfer arm 14 moves toward the die B, the pin 65 will move toward the right to cause lever 51 to expel the workpiece into the die opening.

It should be understood that other equivalents of the lever 51 could be incorporated to accomplish the same result, but the use of a lever is preferred because of its simplicity.

Referring now to FIG. 8, there is shown another embodiment according to the invention. In this embodiment a pin is slidably held within opening 60 in the transfer fingers. As the transfer fingers advance toward the die, the pin 75 engages the die bed and causes the workpiece to be ejected. In order to pick up a workpiece at die A using the embodiments shown in FIGS. 7 and 8, the transfer arm is preferably gradually moved outwardly from die A as the workpiece is inserted therein.

It will therefore be seen that separate means, apart from the punch, are provided in a transfer mechanism for pushing a workpiece into a die. This is particularly important when short-shanked workpieces are to be formed since the dimension of the workpiece may not be sufficient to permit a punch to be employed to securely position the workpiece in the die prior to the fingers 13 being removed.

From the foregoing description, it will thus be seen that the objects set forth, among those made apparent from the preceding description, are efficiently attained and since certain changes may be made in the constructions set forth, without departing from the spirit and scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

It will also be understood that the following claims are intended to cover all the generic and specific features of the invention described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. In a transfer arm mechanism for receiving a workpiece from a first die, then moving the workpiece in front of a second die and then inserting the workpiece into the second die upon the advance of the transfer arm mechanism toward said second die, the improvement comprising two transfer fingers spaced apart from each other at the ends thereof and adapted to receive and hold a workpiece between said finger ends, a rod support by one of said fingers and a pivotally mounted lever supported on said rod, said lever having one end thereof movable between said finger ends, and first means for pivoting said lever to engage a workpiece held by said finger ends as the transfer arm mechanism moves toward said second die to insert a workpiece into said second die.

2. In a transfer arm mechanism according to claim 1, in which said first means comprises a rod slidably supported by one of said transfer fingers and adapted to engage said lever to pivot the same upon the advance of said transfer arm mechanism toward said second die.

3. In a transfer arm mechanism according to claim 1, in which said first means comprises a rod supported by said second die and which is positioned to pivot said lever upon the advance of said transfer arm mechanism toward said second die.

2,328,699 9/1943 Wilcox 10-166 2,528,330 10/1950 Bechler 10166 2,791,786 5/1957 Hoyt et al. 10-166 X LEONIDAS VLACHOS, Primary Examiner.

US. Cl. X.R. 

